Labor’s lead candidate says voters can’t trust his party, the Palmer United party (PUP) candidates have gone missing, the Greens candidate is DJing, 75 people get to vote twice and the whole thing is an unprecedented rerun because the Australian Electoral Commission (AEC) messed up last time. Oh, and it could have a critical impact on how the government gets its legislation through the upper house. The West Australian Senate poll would have jumped the shark, if the state wasn’t culling them.

The outcome is extremely difficult to predict. Most observers, asked to hazard a guess, say the Coalition could get three of the six Senate seats, Labor two and the Greens one.

But the PUP has spent more on advertising than all the other parties put together – spruiking populist promises the party is unable to deliver – Labor suffered a disastrous final day of campaigning with the publication of lead candidate Joe Bullock’s speech criticising his own party, all parties are concerned fatigued voters might fail to show up to vote and there are 77 candidates running, with the final seats determined by the order in which they are eliminated and their preferences distributed. So the final two seats could go any which way.

Whatever happens in the rerun – called because the AEC lost 1370 WA Senate votes in the general election – the result will determine the make-up of the crossbench in the Senate that will sit from July, upon which the government relies to pass its legislative agenda.

Already in the Senate that will sit from July are the two PUP senators-elect – former rugby league player Glenn “the brick with eyes” Lazarus, and Tasmanian Jacqui Lambie. They will be joined by the “motoring enthusiast” Ricky Muir, who starred in a YouTube video in which he playfights with kangaroo poo and who – after the election – entered a still-unclarified voting “alliance” with Palmer. Also elected is the pro-gun, pro-free market Liberal Democrat David Leyonhjelm and the Family First party’s Bob Day.

The Senate numbers mean that if the final seat falls to the PUP this combination of crossbenchers will be able to pass government bills.

But if the Greens win and Labor regains its traditional second seat, the veteran South Australian independent senator Nick Xenophon and the Victorian DLP senator John Madigan will be dealt back into the mix. This scenario would also mean Xenophon and Madigan could join Labor and the Greens to achieve the necessary 38 votes to block legislation – for example the bill seeking to abolish the Clean Energy Finance Corporation.

The government has argued that a vote for the Coalition would guarantee the abolition of the carbon and mining taxes. Labor has sought to make the campaign a “referendum” on the tough spending cuts expected in the federal budget and the Greens have appealed to voters to elect Scott Ludlam as a “brake” on the Abbott government.

Voting is compulsory for the almost 1.5m Western Australians on the electoral rolls, but both major parties have been concerned turnout could be low.

Palmer’s ad blitz has claimed his party would return a higher share of GST revenue to the west – something that would require the agreement of the other states, which would lose money. Palmer also dominated the airwaves during the final days of the campaign, with his candidates appearing before the media on only a couple of occasions in far-flung parts of the state and refusing all requests for interviews.

Labor’s campaign suffered a setback on the final day when a speech by its lead candidate, right-wing unionist Joe Bullock, emerged in which he said “working people” are right not to trust the Labor party to look after their interests and he thinks Tony Abbott has good “core beliefs” and could “potentially be a very good prime minister”.

And 75 voters at an aged care home had to vote twice when their initial ballots were put into an unsecured ballot box.